https://qooah.com/2015/11/03/%e7%b4%85%e7%b1%b3note-2-%e5%9c%8b%e9%9a%9b%e7%89%88%e7%99%bc%e4%bd%88-%e9%a6%99%e6%b8%af%e5%8f%8a%e9%a6%ac%e6%8b%89%e5%83%b9%e6%a0%bc%e5%85%ac%e4%bd%88/